Electric lamp manufacture



March 22, 1949. v, PLAGGE 2,464,990

ELECTRIC LAMP MANUFACTURE Filed Aug. 28, 1945 ATTOR N EY Patented Mar. 22, 1949 ELECTRIC LAMP MANUFACTURE Vernon L. Plagge, East Orange, N. J assignor to Westinghouse Electric Corporation, East Pitts burgh, Pa., a corporation of Pennsylvania,

Application August 28, 1945, Serial No; 613,107

27 Claims. 1

This invention relates to incandescent electric lamps and, more particularly, to such adapted to function as head lamps for vehicles.

The principal object of my invention, generally considered, is to cheapen and facilitate the manufacture of lamps of the sealed beam type by making the reflector and lens portions of soft glass and the light-source supporting or mount with a conventional stem, all of said parts being secured together by a low-softening-point sealing glass.

Another object of my invention is to provide an incandescent electric lamp of the vehicle head lamp type, in which the light source'is supported on a conventional stem of soft glass, which engages the outside or inside of the reflector portion, and is secured thereto by a low-softeningpoint sealing or brazing glass.

A further object of my invention is to employ a conventional stem holding the light source of a sealed beam lamp, which stem is unprovided with a flared end and connected to the inside of the reflector portion by sealing or brazing glass of Iow-softening-point.

A still further object of my invention is to provide a sealed beam lamp in which the relationship between the reflector and lens portions, prior to uniting the same, is maintained by a flange on one of said portions within which the other portion fits.

Other objects and advantages of the invention, relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawing:

Fig. 1 is an axial sectional view, with parts in elevation, of a lamp of the sealed beam type, embodying my invention.

Fig. 2 is a fragmentary sectional view of portions of the connected reflector and lens of the lamp, but showing a modification.

Fig. 3 is a view corresponding to Fig. 2, but showing another embodiment of the invention.

Fig. 4 is a transverse sectional view on the line IVIV of Fig. 1, in the direction of the arrows.

Fig. 5 is a fragmentary View of a portion of the lamp of Fig. 1 adjacent the base, but on a larger scale.

Fig. 6 is a fragmentary portion of a lamp, as in Fig. 1, but showing another embodiment.

Fig. 7 is a view corresponding to Fig. 6, but showing a further embodiment.

Fig. 8 shows a construction corresponding generally to Fig. '7, but slightly modified.

In the well-known sealed beam lamps for automobile head lights, it has been customary to make the reflector and lens portions of hard glass, and secure them together by fusing adjacent surface portions. It has also been the practice to support the light sources in such lamps on leads extending from metal contact terminal devices, including skirt portions of metal of suitable coeflicient of expansion for sealing into the lamp envelope, and having sharp edge portions embedded in the glass of the reflector portion. Such construction is relatively expensive because of the use of hard glass and special alloy members of proper coefiicient of expansion for sealing thereto. In accordance with the present invention, such special members are avoided, hard glass is replaced by soft glass, and the parts of the lamp are held together by a sealing or brazing vitreous material or glass of low softening point, preferably considerably lower, say about 200 C. lower than the glass parts which are held together thereby. The coefificient of expansion of the sealing glass is close enough to that or those of the parts being united to avoid subsequent cracking or separation thereof.

Referring to the drawing in detail, like parts being designated by like reference characters, and first considering the embodiment illustrated in Figs. 1, 4, and 5, there is shown lamp ll of the sealed beam type comprising a concave preferably parabolic reflector portion I2, formed of translucent vitreous material, such as soft glass, the inner surface of which has a coating I3 of specular metal, a lens or cover glass portion l4, desirably formed of transparent or translucent vitreous material such as soft glass, and a mount l5. The reflector and lens portions desirably fit together, as by having a peripheral flange IS on one of said members nestingly or closely receiving the rim portion of the other, as illustrated, thus initially positioning them in proper relationship, independently of the sealing means later described. In this embodiment, the lens portion I4 has a flange l6 receiving the edge portion of the reflector l2.

The reverse construction is illustrated in Fig. 2, in which the reflector l2 has a flange I6 receiving the edge portion of the lens M. The nested reflector and lens portions are in these embodiments united by layers of sealing glass I1 and li positioned between adjacent spaced surfaces of the portions which are angularly disposed with respect to the flange, IE or Hi as the case may be. The sealing glass is desirably of special character so that it softens at a temperature considerably lower than the soft glass forming the parts being aecgeao iii united, and has a coefficient of expansion sufli-= ciently close to that of said parts that it func tions for the desired purpose without cracking or separating therefrom upon cooling.

The light source, as is usual in such lamps, comprises a major or in-focus filament l supported by leads l9 and 2!] extendin through a press 22 of the mount it, the exterior portions of said leads continuing to exterior contact members 23 and 2d projecting from a base 25. The

base is formed of Bakelite" or other suitable insulating material and fits over the boss it pro jecting from the convex portion of the reflector 92. The boss desirably has a shoulder 2i] engaged by the rim ofthe base 25, the base being secured to said boss by basing cement or other suitable connecting material The boss 26 is hollow and thus provides a pocket 20 suficiently deep to receive the stem 3i carry ing the exhaust tube 20 of the mount iii, the bottom of said pocket being defined by an irrturned flange on which the stem 3i rests, and which is sealed thereto by special sealing or brazing glass which may correspond with the glass Ill.

The stem ill also carries an additional lead passing through the press 22 and with its outer end connected to a third contact 35, its inner end, together with an auxiliary lead branching from the lead 2i, serving to support the minor or meeting filament 371 which is slightly out of focus with respect to the reflector l2.

Fig. 3 shows a construction similar to Figs. 1 and 2, except that the sealing glass li is mainly received in a pocket 38 in one of the connected members, in this instance the lens it", and a bead, boss or flange lii on the other member embedded therein, but said pocket, if desired, could be formed in the reflector [12 Fig. 6 shows a modification in which the mount 65" comprises a soft glass disk 80 through which leads l0 and 2H extend to support the filament forming the light source l8, said mount as in the preceding embodiment including an exhaust tube 20 which, with the outer portions of the leads 59 and M project through an aperture provided by the inwardly extending flange 32 on the base supporting boss 26. Although only one filament has been shown in the present em bodiment, it will be understood that two filaments, as in the first embodiment, are desirably employed when used for a vehicle head lamp.

Fig. 7 shows a construction similar to that of Fig. 1 except that the stem Si has an outwardly projecting flange 4i over which the sealing glass 33 is placed for securing the mount W to the boss 26 of the reflector portion 52 Fig. 8 shows an embodiment similar to that of Fig. 7, except that the flange M on the stem l engages the outer surface, rather than the inner surface, of the boss 26 projecting from the reflector I2 and the sealing glass 33 is applied over the outer or lower surface of said flange and confined by a peripheral flange 32 on said boss.

From the foregoing, it will be seen that I have improved on the construction of sealed-beam" lamps by not only substituting soft glass for hard glass and eliminatin special members formed of expensive alloy, but I have facilitated the process of uniting the parts by using readily-fusible sealing glass for that purpose, rather than making it necessary to fuse the abutting surfaces of the parts.

In accordance with previous practice, it was necessary to use hard glass because glass of low expansion was necessary when the parts were connected by fusion at abutting surfaces. If such mode of connection were attempted with soft glass, cracks would result due to the greater ex pansion. However, if it is desired to still use parts of hard glass, but otherwise connect them in accordance with my invention, I may use as a sealing glass such manufactured by the Corning Glass Works as No. 775, and employ it for brazing or sealing together hard glass parts made of such glass as Corning No. 172.

However, a preferred embodiment of my invention comprises using a soft glass, such as Corning No. 008 lime glass, for the lens and re flector portions. In fact, any soft glass composition with a softening point of not lower than 695 (3., and with an expansion coefficient be tween 0 and 300 C. of from 88 to Sex 10- is suitable for the purpose.

As for the vitreous material or glass used as the sealing or brazing medium, I have employed a special glass with essentially the same expansiv ity as the glass parts being secured together, and with a softening point at least 200 C. lower than that of said glass parts. Such a glass may that manufactured by Corning as No. X750 or its equivalent. in other words, a suitable glass may be manufactured by using a large pro portion of lead oxide, PbO, relatively small proportions of silica and alumina, and still smaller proportions of alkali and boric oxide.

The method of assembly for a lamp as illustrated in Figs. 1, 4 and 5, is to place the mount it in position in the pocket 29 of the reflector portion and, while the same is held in place as by a suitable jig, pour a small quantity of molten sealing glass 33 in said pocket so that it unites the lower edge portion of said stem 3! to the boss 26. As an alternative, the reflector portion may be made by the manufacturer with a coating of sealing glass 33 at the place illustrated, as well as a coating of sealing glass l l, and the parts may be assembled and merely heated until a sealing glass, but not the glass forming the parts to be united, softens or melts to cause union of said parts. After cooling, the bulb so formed is evacuated through the exhaust tube, and filled with inert gas in accordance with customary practice.

Although preferred embodiments of my invention have been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims.

I claim:

1. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stem sealed to said reflector portion by vitreous material having a softening point about 200 C. lower than that of the parts sealed together, leads extending from said stem, and a. light source supported on said leadsand positioned in said enclosure in definite optical relationship to said reflecting surface.

2. An electric lamp comprising a soft glass reflector portion having a concave surface with a reflecting coating, a soft glass cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a soft glass stem sealed to said reflector portion by glass of considerably lower softening point, leads projecting from said stem, and a light source supported on said leads and positioned in said enclosure in definite optical relationship to said reflecting surface.

3. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with an inturned flange, a translucent vitreous cover hermetically healed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stern engaging the inturned flange on said boss and sealed thereto by vitreous material having a softening point considerably lower than that of the parts sealed together, leads extending from said stem, and a light source supported on said leads and positioned in said enclosure in definite optical relationship to said reflecting surface.

4. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating a hollow boss projecting from the convex side of said reflector portion and formed with an inturned flange, a translucent vitreous cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stern having a flared portion resting on and sealed to the inner surface of said inturned flange by vitreous material having a softening point considerably lower than that of the connected parts, leads extending from said stem, and a light source supported on said leads and positioned in said enclosure in definite optical relationship to said reflecting surface.

5. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with a central aperture, a translucent vitreous cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stem passing into said aperture, engaging said boss and sealed thereto by vitreous material having a softening point considerably lower than that of the connected parts, leads extending from said stem, and a light source supported on said leads and positioned in said enclosure in deflnite optical relationship to said reflecting surface.

6. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with an inturned flange leaving a central aperture, a translucent vitreous cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stem engaging said inturned flange and sealed thereto by a vitreous material having a softening point considerably lower than that of the connected parts, leads extending from said stem, a light source supported on said leads and mounted in said enclosure in definite optical relationship to said reflecting surface, a base telescoping with a portion of and secured to said boss, contact elements carried on the outside of said base, and means respectively connecting said leads to said contact elements.

7. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover portion, one of said portions having a flange nestingly encircling a peripheral part of the other portion to initially accurately position the portions in proper relationship, said nested portions having adjacent spaced surfaces angularly disposed with respect to said flange, and vitreous material having a softening point considerably lower than that of said nested portions, positioned between said spaced surfaces, and forming an enclosure by hermetically sealing said cover portion to the rim of said reflector portion.

8. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover portion hermetically sealed, by materialhaving a softening point considerably lower than that of the connected portions, to the rim of said reflecting portion and formin an enclosure therewith, said cover portion having a flange closely encircling a peripheral part of the other portion to initially accurately position the portions in proper relationship independently of the sealing means.

9. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover portion hermetically sealed, by material having a softening point considerably lower than that of the connected portions, to the rim of said refleeting portion and forming an enclosure therewith, said reflector portion having a flange closely encircling a peripheral part of the other portion to initially accurately position the portions in proper relationship independently of the sealing means.

10. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover portion, means to initially accurately position the portions in proper relationship independently of the sealing means, said positioned portions having adjacent spaced surfaces angularly disposed with respect to said positioning means, and vitreous material having a softening point considerably lower than that of the positioned portions, disposed between said spaced surfaces, and forming an enclosure by hermetically sealing said cover portion to the rim of said reflector portion.

11. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover portion hermetically sealed to the rim of said reflector portion, by vitreous material having a softening point considerably lower than that of the connected parts, and forming an enclosure therewith, said cover portion having a flange closely encircling a peripheral part of the reflector portion to initially accurately position the portions in proper relationship independently of the sealing means.

12. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a translucent vitreous cover portion hermetically sealed to the rim of said reflecting portion, by vitreous material having a softening point considerably lower than that of the connected parts, and forming an enclosure therewith, said reflector portion having a flange closely encircling a peripheral part of the cover portion to initially accurately position the portions in proper relationship independently of the sealing means.

13. An electric lamp comprising a concave vitreous reflector portion having an inner surface with a reflecting coating, a translucent vitreous cover portion hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, one of said portions having a groove receiving vitreous material having a softening point considerably lower than that of the parts 7 sealed together, the other having a boss received in said groove and embedded in said vitreous material of considerably lower softening point.

14. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with an inturned flange defining a central aperture, a translucent vitreous cover hermetically sealed to the rim of said reflector portion, and a mount comprising a stem carrying an exhaust tube passing through said aperture, and stem-carried lead-in conductors, the inner portions of which serve to support a light source and the outer portions of which pass through said aperture with said exhaust tube, said stem being sealed to said reflector portion by vitreous material having a softening point considerably lower than that of the connected parts.

15. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with an inturned flange defining a central aperture and an annular depression at the base of said boss, a translucent vitreous cover hermetically sealed to the rim of said reflector portion, and a mount comprising a stem seated in said depression and carrying an exhaust tube passing through said aperture, and stem-carried lead-in conductors, the inner portions of which serve to support a light source and the outer portions of which pass through said aperture on opposite sides of said exhaust tube, the peripheral portion of said stem being sealed to said reflector portion by vitreous material havingla softening point considerably lower than that of the connected parts.

16. The method of making an electric lamp comprising forming a reflector portion with a hollow. boss projecting from a convex surface and a reflecting coating on a concave surface thereof, fitting a vitreous stem in said boss, and pouring molten vitreous material which has va softening point considerably lower than that of the associated parts sealed together. around said stem to secure it to said boss.

17. The method of making an electric lamp comprising forming a reflector portion with a hollow boss projecting from a convex surface and a reflecting coating on a concave surface thereof, placing a coating of vitreous material which has a softening point considerably lower than that of said reflector portion on the inside of said boss, fitting a vitreous stem in said boss, so that it engages said low softening point material, and heating without softening the assembled parts until said low softening point material effects sealing therebetween.

18. The method of making an electric lamp comprising forming a reflector portion with a reflecting coating on a concave surface thereof, forming a cover portion with an outer peripheral surface shapd to seat on the outer peripheral surface of said reflector portion, one of said portions having a peripheral flange of a size to closely encircle a peripheral part of the other portion, coating at least one of said peripheral surfaces with vitreous material which has a softening point considerably lower than that of the parts to :be united, assembling so that the peripheral flange receives said peripheral part andeffects accurate positioning of the cover portion with respect to said reflector portion independently of said low softening point material, and heating without softening the assembled parts until said low softening point material effectssealing therebetween.

19. The method of making an electric lamp comprising forming a reflector portion with a hollow boss projecting from a convex surface and a reflecting coating on a concave surface thereof, placing a coating of vitreous material, which has a softening point considerably lower than that of said reflecting portion, on the inside of said boss, fitting a vitreous stem in said boss, so that it engages said low softening point material, forming a cover portion with an outer peripheral surface shaped to seat on the outer peripheral surface of said reflector portion, placing a coating of said low softening point material on one of said surfaces, assembling, and heating without softening the assembled parts until said low softening point material effects sealing therebetween.

20. An electric lamp comprising a vitreous reflcctor portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with an inturned flange, a vitreous cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stem formed with an outturned flange engaging the inturned flange on said boss and sealed thereto by vitreous material having a softening point considerably lower than that of the connected parts, leads extending from said stern, and a light source supported on said leads and positioned in said enclosure.

21. An electric lamp comprising a vitreous reflector portion having a concave surface, a hollow boss projecting from the convex side of said reflector portion and formed with a central aperture, a groove in the outer end of said boss around said aperture, a vitreous cover hermetically sealed to the rim of said reflector portion and forming an enclosure therewith, a vitreous stem passing through said aperture and with an outstanding flange lying in said groove, vitreous material having a softening pointconsiderably lower than that of said reflector portion and stem sealing said flange in said groove, leads extending from said stem, and a light source supported on said leads and positioned in said enclosure.

22. The method of making an electric lamp comprising forming a reflector portion with a hollow boss projecting from a convex surface, fitting a vitreous stem portion in said boss, placing vitreous material, which has a softening point considerably lower than that of said reflector portion, on said boss adjacent said stem and heating said low softening point material so that it effects sealing between said portions without softening the latter.

23. The method of making an electric lamp comprising forming a reflector portion with a hollow boss projecting from a convex surface, placing a vitreous stem portion in said boss, plac ing vitreous material adjacent said boss and stem portion, said vitreous material having a softening point considerably lower than that of said reflecting and stem portions, forming a cover portion with an outer peripheral surface shaped to seat on the outer peripheral surface of said reflector portion, placing some of said low-softening-point material between said peripheral surfaces, and heating to soften said placed material and unite, without softening, said cover, reflector and stem portions, by said low-softening-point material.

24. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion, a vitreous stem received in and engaging said boss and sealed thereto by vitreous material having a softening point considerably lower than that of the parts sealed together, leads extending from said stem, and a light source supported on said leads in definite optical relationship to said reflecting surface.

25. An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion, a vitreous stem having a flared portion and received in said boss, said flared portion being sealed to said boss by vitreous material having a softening point considerably lower than that of the connected parts, leads extending from said stem, and N ber Name Date a light source supported on said leads in definite 488,635 Prentiss Dec. 27, 1892 optical relationship to said reflecting surface. 1,861,167 Vello Ma 31, 1932 26. An electric lamp comprising a soft glass 25 2,148,314 Wright Feb. 21, 1939 reflector portion having a concave surface with a 2,148,315 Wright Feb. 21, 1939 reflecting coating, a soft glass stem sealed to said 2,362,171 Swanson Nov. 7, 1944 reflector portion by glass having a softening point 2,398,968 Singer Apr. 23, 1946 of about 200 0. lower than that of the parts Disclaimer 2,464,990.-Vern0n L. Plagge,

sealed together, leads projecting from said stem, and a light source supported on said leads in deflnite optical relationship to said reflecting surface. 27; An electric lamp comprising a vitreous reflector portion having a concave surface with a reflecting coating, a hollow boss projecting from the convex side of said reflector portion and formed with a central aperture, a vitreous stem passing into said aperture and sealed to said boss by vitreous material having a softening point considerably lower than that of the connected parts, leads extending from said stem, and alight source supported on said leads in definite optical relationship to said reflecting surface.

VERNON L. PLAGGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS East Orange, N. J. ELECTRIC LAMP MANUFAC- TUBE. Patent dated Mar. 22, 1949. Disclaimer filed Mar. 5, 1952, by the assignee, Westinghouse E leetrie Corpomtion.

Hereby enters this disclaimer to claim 13 of said patent.

[Ofiicial Gazette April 8, 1952.] 

